Question 1204613
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{{{sin(a+b) = sin(a)cos(b)+cos(a)sin(b)}}} One of the many trig identities


{{{sin(x+2pi/3) = sin(x)cos(2pi/3)+cos(x)sin(2pi/3)}}}


{{{sin(x+2pi/3) = sin(x)(-1/2)+cos(x)(sqrt(3)/2)}}} Use the unit circle


{{{sin(x+2pi/3) = expr(-1/2)*(sin(x)-sqrt(3)*cos(x))}}}
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